1. Field of the Invention
The present invention relates generally to medical devices and methods. In particular, the present invention relates to an oral device that may be held in the mouth of a patient to reduce the incidence of obstructive sleep apnea or snoring.
Obstructive sleep apnea (OSA) is a serious medical condition resulting from a temporary airway blockage which occurs as a patient sleeps. The airway blockage usually occurs between the soft palate and/or the back of the tongue and the pharynx. As the patient breathes, the reduced area in the upper airway can cause snoring, and more seriously, OSA. Sleep disruption caused by OSA can result in severe daytime sleepiness, chronic fatigue, headaches, depression, accidents, injuries, and of particular concern, OSA can reduce the amount of oxygen entering the lungs causing hypoxia. Hypoxia, in turn, can lead to pulmonary hypertension, heart disease, and stroke.
Numerous invasive and less invasive treatments have been proposed for OSA. Of particular interest to the present invention, “continuous positive airway pressure” (CPAP) delivers a continuous stream of pressurized air directly to the person's upper airway. The positive pressure maintains patency of the airway and inhibits the airway collapse associated with OSA. Although generally effective, CPAP suffers from a number of drawbacks that have led to a high level of non-compliance. The patient must wear a bulky facial mask which can be uncomfortable, and the system generates noise that can make falling asleep difficult. CPAP is also difficult to use because the mask requires careful fitting to avoid air leaks and facial discomfort and because the mask can easily be dislodged during sleep. Moreover, a number of unpleasant side effects, such as sore throats, dry throat and eyes, headaches, and skin rashes from the mask frequently occur. These problems have resulted in a high level of non-compliance with CPAP therapy.
As an alternative to CPAP, the use of mandibular advancement devices, often referred to as a mandibular splint or a mandibular advancement splint, has been proposed. A mandibular advancement device is an oral appliance worn in the mouth over the upper and lower teeth. The device treats snoring and sleep apnea by moving the lower jaw forward slightly, which tightens the soft tissue and muscles of the upper airway to inhibit obstruction of the airway during sleep. The tightening created by the device may also suppress vibrating of the soft tissues of the upper airway as air passes over them, which is the most common cause of loud snoring. While often effective, such mandibular advancement devices can cause significant jaw discomfort and can cause teeth to shift over time, leading to significant dental problems.
A recent significant improvement in the treatment of sleep apnea is described in U.S. Pat. Nos. 8,074,656; 8,074,656; and 8,122,889, U.S. Patent Publication 2012/0017917, and copending application Ser. No. 13/593,137, each assigned to the assignee of the present application, the full disclosures of which are incorporated herein by reference. These patents and applications describe engaging a lateral element across a medial region of the tongue to create a clearance above the tongue. By drawing a vacuum in the oral cavity, the soft palate can be drawn forward to open the airway. While very successful in many patients, the treatment is not fully effective in some patients.
For these reasons, it would be desirable to provide alternative and improved methods and apparatus for treating obstructive sleep apnea and snoring. The methods and devices should be non-invasive and require no surgery or permanently implanted components. In addition, the methods and devices should be minimally intrusive with components that are comfortable and quiet so that disruption of the patient's sleep is minimized. The methods and devices should reduce any risk of tooth displacement associated with mandibular advancement or other causes. Moreover, the methods and devices should avoid contacting the portions of the oral cavity that trigger the gag reflex. The methods and systems should also be simple to implement and be effective to significantly improve patency of a patient's airway during sleep in a broad population of patients suffering from sleep apnea. At least some of these objectives will be met by the inventions described hereinafter.
2. Description of the Background Art
U.S. Pat. Nos. 8,074,656; 8,122,889; and 8,122,890; U.S. Patent Publication No. 2012/007917; and co-pending application Ser. No. 13/593,137, each assigned to the assignee of the present application, are described above. U.S. Patent Publication Nos. 2005/0028826; 2007/0074729; 2010/0043805; and 2011/000495, the full disclosures of which are incorporated herein by reference, describe various mandibular advancement devices.